AbstractIn this contribution, we present a new geological map of the Jurassic formations exposed in the central sector of the Montagna dei Fiori anticline, in the Central Apennines. Mapping activity was devoted to better detail the extensional fault patterns still preserved in the anticlinal core and to separate dolostones from the parent limestones. The results of our work indicate that the lower half of the Corniola Fm. is systematically dolomitized in the study area. On the other hand, the underlying Calcare Massiccio Fm. is strongly dolomitized in the Castel Manfrino and Osso Caprino hill area, whereas limestone dominates to the east and to the south. Our new map supports block faulting induced by Jurassic rifting as the cause of the Calcare Massiccio Fm. map pattern, rather than gravity-driven block collapse, as alternatively proposed.

AbstractTwo volcaniclastic deposits, ROC and SBA, in the Oligo-Miocene succession of the Southern Apennines, between the Apulia and Campania regions, have been studied for the first time. Mineral composition, SEM-EDS and LA-ICP-MS analyses, for major and trace elements, respectively, allowed recognizing magmatic products of typical calc-alkaline to high-K calc-alkaline affinity. ROC glasses have a restricted compositional range in the rhyolitic field whereas SBA glasses show a wide compositional range from andesite to rhyolite, with dacite as the most common composition. Fission-track dating of apatite in the SBA deposits yielded an age of 21.7 ± 2.2 Ma, which is comprised between the Chattian and the Burdigalian. Biostratigraphic analyses in sedimentary layers adjacent to ROC layers indicate they were deposited not before Burdigalian. A provenance analysis of the studied volcaniclastics in relation to the possible source areas of the Mediterranean and neighbouring areas was performed. On the basis of time constraints, mineral and trace element composition a convincing correlation of the ROC deposits with potential source areas did not emerge. Instead, a provenance from the southwestern and northwestern Sardinian volcanic centres was favoured for the SBA volcaniclastic deposits. This hypothesis is compatible with the Oligo-Miocene paleogeographic reconstructions, that show the proximity of the Apennine sedimentary basins to Sardinia before the opening of the Tyrrhenian sea.

AbstractThe Mt. Modino Unit succession (Northern Apennines) is mainly composed of turbiditic sediments deposited during the collisional and post-collisional stages of the Northern Apennines fold-and-thrust belt. Within this succession we have studied a thick interval of shales with arenitic beds, marls and arenites, of the Fiumalbo Shale, the Marmoreto Marl and the Mt. Modino Sandstone formations. Calcareous nannofossil assemblages of the eight investigated stratigraphic sections contain middle-late Eocene to Oligocene-early Miocene biozones. Zones CNE12 to MNN1 have been identified through quantitative analyses of a set of 200 samples, and the precise ages of the Fiumalbo Shale, the Marmoreto Marl and the Mt. Modino Sandstone were identified as well.

The biostratigraphic analyses enable stratigraphic correlations between the investigated sections which were used to propose a stratigraphic architecture of the Mt. Modino Unit succession.

Physical and biostratigraphic data available for the Mt. Modino Unit succession suggest a subsiding wedge-top basin fed since the Rupelian by both Apennine and Alpine sources. After the late Oligocene shortening phase, the Mt. Modino Basin occupied the inner part of the foredeep basin, sharing the same turbiditic deposits with the Macigno formation.

AbstractThe Monte Alpi is a key area to decipher the structural setting of the southern Apennines fold-and-thrust belt. There, high-angle faults juxtapose Mesozoic carbonates of the inner Apulian Platform, and their terrigenous Messinian sedimentary cover, against the allochthon terranes. In the recent past, two main tectonic models related to the evolution of the Monte Alpi area ascribed the significant exhumation of the Apulian carbonates to two different mechanisms. The first one, highlighted the role of high-angle faults, which affect and cross-cut both carbonates and allochthon terranes. The second model, inferred the significant exhumation of the Apulian Platform carbonates as due to low-angle extensional faulting. In light of the aforementioned discrepancies, the present work shows the results of original field and laboratory analyses aimed at reconstructing the structural setting of both Apulian carbonates and allochton terranes. In particular, two different folding stages and the geometry of the thrust sheets are assessed, by means of detailed field and micro-structural analyses, for the allochton terranes. In the Apulian carbonates, both attitude and kinematics of the syn-sedimentary high-angle faults bounding the Upper Messinian deposits are documented. Furthermore, the tectonic structures associated to the contractional, strike-slip and extensional stages are distinguished based on their abutting and crosscutting relationships. Finally, the results of such a work are discussed in terms of the time-space evolution of deformation in the Monte Alpi area; five main tectonic stages are deciphered for the Pre-Pliocene to Holocene times.

AbstractCelebrating the centennial of Domenico Lovisato's death (1842- 1916), this paper highlights the role played by this eminent Italian geologist as a pioneer for the geological knowledge of Calabria region (Southern Italy), a geologically complex area which became the subject of a long-lasting and still continuing debate.

Lovisato spent only few years in Calabria (1876-1878) teaching as high school professor of mathematics; this period marked a turning point for his scientific growth representing a switch for his career from avocational to full-time geologist. This experience granted him the involvement in the academic career, with the enrollment in the niversity of Sassari and Cagliari as Professor of Mineralogy and Geology (from 1878 until his death, in 1916). Lovisato must be acknowledged as the author of the first 1:50,000 geological map of the Calabria region. As such, he should be mentioned for his ethic approach towards environment, anticipating the catastrophic effect of natural phenomena and the modern concepts of geoethic.

AbstractIn this paper we report new stratigraphic data related to a new geological map of the Miocene Gorgoglione Basin of southern Italy, traditionally considered as a piggy-back or wedge-top basin filled by a turbidite-like succession. Well exposed outcrops in the study area (eastern sector of the basin) show four unconformities in the Castelmezzano-Pietrapertosa area. Two of these unconformities pass to paraconformities southeastward, in the Cirigliano-Gorgoglione area. Based on new stratigraphic data the "succession of the Gorgoglione Flysch" can be divided into different informal units: Val Miletta formation and Gorgoglione supersynthem. The latter can be subdivided into the Cirigliano and Castelmezzano synthems. The previously established Cirigliano synthem is here divided into three subsynthems. The lowermost sediments of the Gorgoglione Flysch on the eastern sectors correspond to a complex unit (Val Miletta formation) including Numidian-like quartzarenites, Gorgoglionelike sandstones, and, at the top of the formation, an olistostrome of varicoloured clays, belonging to the Argille Variegate Group. The stratigraphic analyses and the biostratigraphic results based on calcareous plankton assemblage, improve the reconstruction of the geometries of the sedimentary bodies and the time-space facies evolution of the synthems. Sedimentologic and petrographic characters of the upper part of the Castelmezzano synthem show a clear fining and thinning upward trend. Medium- and fine-grained arenites, varying in composition from quartz sandstones to siltstones and shales, are locally marked by abundant planktonic foraminifera and are interpreted as contourites. Moreover, the relationships between tectonics and sedimentation are analyzed. The data are used to propose a scheme of the Burdigalian to Tortonian tectono-stratigrafiphic evolution of the eastern sector of the basin.

AbstractThe digital storage and communication of significant geological data became increasingly more objective and accessible through the development of new technologies or the implementation of already well-known techniques as photogrammetry. Digital acquisition of geometries (both structural and depositional) of significant geological outcrops is deemed necessary, especially if the site concerned is liable to be damaged or hopelessly involved in natural processes of geological and geomorphological evolution. In this paper, we tested the performances of two different open-source software (i.e. VisualSFM and ARC3D) on a small-scale but paradigmatic outcrop in the Umbria- Marche Apennines (Italy). The test showed that ARC3D provides an high-resolution model, employing a relatively short time and requiring a inexpensive hardware support for processing hundreds of photos.

In the text, 3D models of the selected outcrop are reported and discussed emphasizing the potential of the method to highlight structural, sedimentological and paleontological details.

As a result, 3D photogrammetry proved to be a powerful and effective tool to digitally conserve and objectively communicate important geological observations and to facilitate accessibility and dissemination of the collected data within the scientific community.

AbstractThe Burdigalian-Tortonian Epiligurian succession in the Val Marecchia area comprehends different lithostratigraphic units deposited in a wedge-top basin during the northeastern migration of the thrust belt. The succession includes shallow-water carbonates passing to mixed carbonate-siliciclastic and to fine-grained politic sediments, capped by fluvio-deltaic coarse-grained deposits. Detailed field work and stratigraphy has allowed to characterize depositional units and unconformities and to delineate the sedimentary and tectonic evolution of the basin. Tectonics exerted a primary control at different stages. During the Burdigalian, a general uplift of the area allowed the onset of shelfal carbonate sedimentation on underlying Ligurian and Epiligurian deep-water sediments. At the Serravallian the sedimentation was influenced by the thrust reactivations which caused a marked asymmetry in the basin geometry and fill. The subsidence increase in the rear part of the basin determined the deposition of a thick succession of relatively deep fine-grained sediments (up to 800 m water-depth) (Serravallian, MNN6a through MNN6b subzones based on nannofossil biostratigraphy) and fossiliferous clays (lower Tortonian, biozones MNN8b-MNN9). Conversely, uplift is activated in the frontal part of the basin, causing the partial erosion of the Burdigalian-Langhian shallow-water carbonates. A relevant amount of this carbonate detritus is delivered to the foredeep, supplying the Marnoso-arenacea Fm. A general uplift of the area in the late Tortonian leads to the deposition of fluvio-deltaic conglomerates supplied by emerged rear sectors of the basin.

AbstractWe present a petrological study of phyllites from the Variscan basement at Punta Bianca (Northern Apennines). According to the literature the studied rocks are believed to be the result of Alpine and Variscan metamorphism of pre-Carboniferous pelites, which consist of Fe-chlorite, potassic white mica, quartz, minor paragonite, and accessory hematite, rutile, monazite, zircon, xenotime, and florencite. Microstructural observations indicate a main S2 foliation that had overprinted an earlier S1 foliation. The mineral assemblage can be related to both S2 and S1.

Large flakes of relatively Mg-rich potassic white-mica along the two foliations are probably detrital grains that preserved their composition. The calculation of isochemical phase diagrams, their contouring by various mineral chemical parameters and the deformation microstructures of quartz indicate intermediate pressure-low temperature conditions (5-7 kbar and 300-400 °C). The anhedral habit and the very low Pb contents (< 50 ppm) in monazite point to dissolution of this mineral probably during Tertiary times.

AbstractThe "I Sodi" section is exposed in the homonymous quarry in the northern sector of the Siena Basin, one of the most extended Neogene-Quaternary post-collisional basins of the northern Apennines. The section is composed almost exclusively of marine mudstone containing a rich fossil assemblage and has been extensively investigated in past and recent times. It represents a key section to define the time interval of marine deposition in the Siena Basin and more generally in the inner northern Apennines, with important structural and stratigraphic implications.

The marine infill of the Siena Basin is traditionally attributed to the Zanclean-Piacenzian (Pliocene) age. However, recently published data provided a more recent age for the "I Sodi" section (Calabrian, Lower Pleistocene) and, consequently, for the Siena Basin. This paper provides new data on this scientific debate, from sedimentological and biostratigraphical investigations. Analyses of planktonic foraminifera and calcareous nannofossils have been carried out in order to better constrain the depositional age of the section. As a result, this section is now dated more accurately to the Piacenzian and possibly to the lowermost Gelasian in its upper part.

AbstractThe Monte Facito Formation consists of Early-Middle Triassic sediments deposited during the first stages of the continental separation of Africa and Europe. This stratigraphic unit, located at the base of the Mesozoic succession of the Lagonegro Basin, appears as a chaotic complex, severely affected by contractional tectonics, and whose original stratigraphic order is very difficult to determine. Despite these complications, a first attempt to determine stratigraphic order was performed on the southern side of the Monte Facito locality. Another key section considered was the La Cerchiara outcrop. As the Monte Facito section is no longer accessible, the La Cerchiara outcrop remains the only locality were a significant stratigraphic portion of the Monte Facito Formation can be observed. Nevertheless, the problematic way-up of the succession has until now prevented consideration of this outcrop as the main Monte Facito Formation type-succession. Difficulty in determining way-up is a consequence of a lack of high-resolution biostratigraphic dating combined with a paucity of well-preserved way-up sedimentary indicators. A detailed field survey, involving sedimentological, stratigraphic and structural observations, has been conducted with the aim of definitively understanding the correct younging direction of the Monte Facito succession exposed at the La Cerchiara locality. The recognition of well-preserved way-up sedimentary indicators, as well as graded beds and ripples, allows an eastward direction of younging to be attributed to the study succession. These results permit a better understanding of the evolution of the passive northern African palaeomargin during the Triassic period, which led to the opening of the Lagonegro Basin.

AbstractPalaeosol-based correlations within the Late Pleistocene-Holocene alluvial succession along the Reno River, in the southern Po Plain, enabled the identification of depositional cycles falling in the sub-Milankovitch band. Each cycle, composed of overbank and fluvial facies capped by poorly to weakly developed palaeosols, is correlatable upstream to a single fluvial terrace in the Reno River valley and to an individual channel belt close to the valley outlet. Four cycles, dated to about 15-10 (c1), 10-5.5 (c2), 5.5-1.5 (c3) and <1.5 (c4) cal ky BP, respectively, were identified within the Ravenna subsynthem (AES8), an unconformity-bounded unit of the Geological Map of Italy to scale 1:50,000, corresponding to the post-Last Glacial Maximum deposits. This unit, typically wedge-shaped in coastal areas, where it consists of retrogradational (coastal plain and estuarine) deposits overlain by progradational (deltaic) facies, at the basin margin is a mud-dominated alluvial succession deposited atop laterally extensive fluvial-channel complexes. The base of AES8, correlatable to the transgressive surface identified in the coastal area, is a palaeosol dated to about 18-15 ky BP. The bounding surfaces of the high-frequency cycles are diachronous along the Reno longitudinal profile, and not necessary associated to remarkable lithological contrasts, but can be detected even in mud-dominated successions. Climate change likely exerted a major control in triggering alternating phases of river aggradation and degradation, with an increasing contribution of anthropogenic factors since the middle-late Holocene. Based on the correlation of 34 core logs and 33 well descriptions, with the aid of 71 radiocarbon dates, this study highlights to what extent palaeosols can represent powerful stratigraphic tools to identify cyclic patterns in alluvial successions, even at the millennial time scale

AbstractA revision of field data and new biostratigraphic analyses have highlighted that the lowest part of the Poggio Carnaio Sandstone Fm consists of greyish marls, formerly attributed to the Antognola Marl Fm, and that calcareous nannofossil assemblages from these marls as well as from the overlying turbiditic sandstones are characterized by some taxa first occurring in Tortonian. Moreover, the occurrence of Discoaster cf. berggrenii could suggest an age not older than late Tortonian for the studied succession.
The Poggio Carnaio Sandstone Fm, therefore, from its base is not older than Tortonian and constitutes a thrust-top basin unconformable succession, deposited on sub-ligurian units.

AbstractThe Ofanto Basin is an actively evolving intra-chain basin of the Southern Apennines, Italy. It has an elongated shape, about 7 km large and 45 km long, and is E-W striking, representing a marked bend in the NW-SE regular orientation of the south-Apennines morphostructures.
The basin is filled up by Pliocene to Quaternary clay, sandstone, and conglomerate, deposited in both marine and continental environments. The main sedimentary deposits are grouped into six units bounded by stratigraphic discontinuities marked by unconformities and abrupt lithological variations. Three of those discontinuities are recognisable on a regional scale and represent the physical boundaries of three supersynthems, in turn subdivided into synthems and subsynthems by basin-scale unconformities. The sedimentary evolution of the basin is herewith reported. Facies analyses and architecture of the sedimentary bodies revealed that each unit formed different alluvial and deltaic depositional systems located on the southern and northern margins of the basin. The morphology of the northern slope was probably steeper than the southern one. The oldest units were deposited in the Western sector of the Ofanto basin. Starting from the late Zanclean to the early Gelasian, the sedimentary bodies underwent an Eastward shift in their deposition, suggesting a basinward relocation of the depositional systems. Such variations in time and space seem to reflect relevant changes in accommodation space and sedimentary supply during the tectonic evolution of the basin. Eventually, correlations among adjacent basins and the meaning of the discontinuities as former erosional surfaces have been pointed out.

AbstractResedimented calcarenites and hybrid arenites are commonly found interbedded with various Upper Miocene terrigenous units (hemipelagic marls, "brecce della Renga fm.", and siliciclastic turbidites) across the Simbruini Mts. and neighbouring areas of Central Apennines. Their distribution provides evidence for a complex, and rapidly evolving, paleogeography across a region that was experiencing the transition from foreland to accretionary wedge conditions during the Tortonian and Messinian. The bio-sedimentological features of the calcarenites indicate deposition through gravity flows (turbidity currents) sourced by areas of active benthic, heterozoan-type carbonate
production, locally lying at photic depth. Thin-section analysis of >130 samples revealed that the resedimented levels are mainly composed by bioclastic calcarenites, with fragments of bivalves, echinoids, bryozoans, balanids, benthic foraminifera, anellids and red algae, along with subordinate planktonic foraminifera. The calcareous turbidites in the hemipelagic marls (Unità argillosomarnosa) are characterized by the presence of Heterostegina sp., and their main source area was probably lying east, on the undeformed foreland. In contrast, evidence from field mapping, their common association with Cretaceous and Miocene carbonate lithoclasts, and the age of the encasing units, all suggest that the calcarenites in the "brecce della Renga fm." and in the siliciclastic turbidites ("complesso torbiditico altomiocenico laziale-abruzzese") could most likely have a different source.
The presence of a carbonate ridge, corresponding today to the NW sector of the Simbruini range, bordered by normal faults exposing the Cretaceous substrate, is proven proven by mappable paleo - escarpment tracts onlapped by clastic and hemipelagic deposits.
This ridge could have fed surrounding deeper areas with a mixture of lithoclasts and loose bioclastic material, produced through erosion of exposed bedrock coupled with export of sediment that was being produced topping and fringing the footwall blocks and their marginal downsteps. Carbonate production was apparently able to survive for a limited time in small productive areas until the early Messinian, shedding sediment into the siliciclastic foredeep

AbstractFacies analysis and ichnology in a foredeep system of the Lower Miocene Macigno Formation, N of Lake Trasimeno (Umbrian Apennines, Italy), show that ichnoassemblages, developed into several ichnocoenoses - typical ichnotaxa and their stratinomic position in different facies - can be diagnostic indicators for siliciclastic and carbonatic gravity flow deposits. Ichnologic analysis allows defining palaeoecological adaptations in deep-sea burrower organisms, as already applied successfully in other deep-sea environments of Cenozoic turbiditic successions of Italy and Spain.
Fourteen sections of the three members of Macigno Formation, some of these revisited in this work, contain ichnocoenoses, differing among distal lobes, inter-lobes deposits (hemipelagic mud), lobe fringes and mud turbidites. The use of ichnocoenoses (e.g. the Halopoa-Spirophycus-Spirorhaphe ichnocoenosis with the fucusopsis preservation of the ichnogenus Halopoa), described here for the first time, underline, rather than classical ichnofacies (Nereites) or ichnosubfacies, the usefulness of ichnology in foredeep basin analysis.

AbstractThe Upper Valdarno Basin stands out from the Neogene-Quaternary basins of the Northern Apennines given its outstanding fossil mammal record, good quality of natural and artificial outcrops and remarkable chronological control on the basin-fill succession. The present paper aims to summarize the stratigraphic and sedimentological studies focused on the Upper Valdarno Basin during the past decades, and integrate them with recent investigations. The Upper Valdarno Basin is located about 35 km SE of Florence between the Chianti Mountains and the Pratomagno Ridge. It consists of a main asymmetric tectonic depression filled with 550 m of Plio-Pleistocene fluvio-lacustrine deposits (Upper Valdarno Basin s.s.) and a minor basin known as the Palazzolo sub-basin. The Upper Valdarno Basin
fill is made of three unconformity-bounded units, named Castelnuovo dei Sabbioni (CSB), Montevarchi (VRC), Torrente Ciuffenna (UFF) synthems, whereas the Palazzolo sub-basin fill consists of the Fosso Salceto (OLC) and Torrente Ciuffenna (UFF) synthems. The Upper Valdarno Basin formed during Late Pliocene because of the tectonic damming of a northeastward flowing drainage. The early phase of basin development is recorded by the accumulation of fluvial gravels in vallive settings, whereas the definitive of these streams damming caused the development of lacustrine conditions at about 3.1 Ma. The accumulation of deltaic sand fed from the SW margin caused the lake filling and stopped the deposition of the CSB Synthem.
Before 2.58 Ma, a tectonic phase caused uplift of the basin and partial erosion of the CSB deposits. Deposition of the lower part of the VRC Synthem occurred during a marked basin broadening and accumulation of alluvial fan successions, which were capped by aeolian-reworked alluvial sand deposited at about 2.5 Ma. At about 2.3 Ma, a new deformative phase caused further basin widening, erosion along the SW margin and development of a small lake in
the central areas. Deposition of the upper part of the Montevarchi Synthem started just after this tectonic phase and was characterized by development of axial fluvial drainage and marginal alluvial fans.
During the Early Pleistocene (Olduvai Subchron, 1.95-1.78 Ma) a subsidence pulse promoted development of floodplain lakes and swamps in the axial part of the basin, where thick organic-rich mud were accumulated. During late Early Pleistocene the capture of the paleo-Arno River, which started to flow into the basin, caused the development of a marked unconformity. This unconformity was covered by fluvial and alluvial fan deposit in the axial part and along the margin respectively.

AbstractThe Upper Valdarno Basin is located about 35 km SE of Florence between the Chianti Mountains and the Pratomagno Ridge.
The basin fill is made of four synthems named as Castelnuovo dei Sabbioni, Montevarchi, Fosso Salceto and Torrente Ciuffenna synthems. The Castelnuovo dei Sabbioni Synthem (Late Pliocene) consists of coarse-grained, stream gravels grading upwards into sheet-like, alluvial sand. These sands are overlain by a muddy lacustrine unit bearing, at its base, two well-developed lignitiferous seams accumulated in a coastal marsh setting. The lacustrine mud grades upwards into deltaic sand accumulated in a shallow-water delta under repeated lake-level oscillations. The Montevarchi Synthem (Late Pliocene to Early Pleistocene) consists of two portions separated by an unconformity surface passing basinward into a correlative conformity. The lower portion of the Montevarchi Synthem is made of alluvial fan gravel and sand passing upwards into fluvioaeolian sandsheet deposits, consisting of aeolian-reworked, alluvial sand bearing isolated channels. Fluvio-aeolian sandsheet deposits are covered by mollusc-rich, alluvial sand which makes lateral transition into lacustrine muddy deposits. The upper portion of the Montevarchi Synthem consists of fluvial and alluvial fan deposits. Fluvial deposits occupy the axial part of the basin and are referred to sandy channels wandering through a muddy floodplain hosting shallow lakes and swamps. Alluvial fan deposits occur along the basin margins and consist of proximal gravels grading downfan into gravelly sand and a variety of sandy facies. Floodplain lakes deposits are well-developed in the middle part of the upper Montevarchi Synthem and in the Palazzolo sub-basin (Fosso Salceto Synthem), where they are overlain by alluvial-fan gravels. The Torrente Ciuffenna Synthem (Early to Middle Pleistocene) consists of fluvial sediments in axial part of the basin and alluvial fans deposits along the basin margins. The axial fluvial deposits were accumulated by the paleoArno River and consist of gravel and overlying sand. The basal gravels were deposited by low-sinuosity channels, whereas sandy deposits were formed by moderate to high-sinuous channels. The alluvial fan deposits consist of proximal gravels passing downfan
into gravelly sand and sandy facies.

AbstractWe use new structural and apatite fission-track data together with apatite fission-track and (U-Th)/He data from literature to examine the tectonic evolution of the continental Upper Valdarno Basin, in the hinterland sector of the Northern Apennines fold-andthrust belt. This basin is located in-between two structural ridges, the Chianti Mountains to the southwest and the Pratomagno to the northeast. In our interpretation, the Upper Valdarno Basin developed at ca. 3.4-3.3 Ma as pop-down synformal-shaped depression bounded and controlled by oppositely-verging thrust-related structures, namely the thrust system lifting the Chianti Mountains and the southwest-facing backfolds at the base of the Pratomagno. This evolution is compatible with the accelerated exhumation rates at 4-5 Ma documented through apatite fission-track data along both the Pratomagno and Chianti ridges. Shortening suffered by basin deposits is clearly manifested by the outcrop-scale reverse faults and thrust-related folds affecting the Late Pliocene sediments (Castelnuovo dei Sabbioni Synthem), which are well exposed in the Santa Barbara mine. These strongly folded deposits are overlain unconformable by Early Pleistocene sediments (Montevarchi Synthem), which display evidence for syn-depositional normal faulting. This suggests that the Upper Valdarno Basin experienced a phase of normal faulting that started at the base of Pleistocene (ca. 2.6-2.5 Ma) and likely produced the large southwest-dipping "Trappola Fault", which affects the southwestern margin of the Pratomagno displacing the earlier backthrusts and backfolds. Basin evolution can be thus basically framed into a two-phase history, with extensional tectonics superposed onto compressional structures that were deactivated by ca. 2.7 Ma. Being the Chianti Mountains part of the 250 km-long regional line of thrusts and thrust-related folds (the so-called "Tuscan Nappe front"), the results of this study may also involve regional implications, as they would also hint for the tectonic history of other sectors and basins settled along-strike this regional element.

Geometry and kinematics of the Montelanico-Carpineto Backthrust (Lepini Mts., Latium) in the hangingwall of the early Messinian thrust front of the central Apennines: implications for the Apennine chain building

AbstractThe paper updates knowledge on the Montelanico-Carpineto Backthrust, which is confined in the Lepini Mts. thrust sheet, at the hangingwall of the Neogene Latina Valley Thrust Front.
The local stratigraphic setting consists of a pre-orogenic succession of Mesozoic carbonates from the Latium-Abruzzi platform Auct. The carbonates are paraconformably overlain by Miocene ramp limestones, which evolve upwards into planktonic marls. The Sub-Ligurian unit thrusted over this dominantly carbonate succession.
In the Latina Valley, siliciclastic turbidites (Frosinone Formation Auct.), which evolved from the above-mentioned Miocene units, constitute the upper Tortonian foredeep deposits, now preserved in the footwall of the Lepini Mts. thrust sheet. In the Segni-Montelanico area, conglomerates, unconformably overlying the carbonate
bedrock and coeval with the Frosinone Formation, are interpreted as late Tortonian thrust-top deposits (Gavignano and Gorga unit). The Lepini Mts. ridge has two series of distinctive tectonic features: the first is related to the Neogene shortening events due to the Apennine chain building; the other results from Plio-Quaternary extensional events associated with the collapse of the Tyrrhenian margin.
The Montelanico-Carpineto Backthrust, as evidenced by the structural survey, is a compressive fault plane dipping 45°-50° towards NE with a SW-verging dip-slip kinematics. The fault has an offset of about 700 m, ramp geometries and a cut-off of about 20°. The Montelanico-Carpineto Backthrust and the Latina Valley Thrust Front define a pop-up structure. The presumable age of the Montelanico-Carpineto Backthrust is the early Messinian, because the late
Tortonian Gavignano and Gorga unit is involved in its brittle shear zone. This implies that the formation of the Montelanico-Carpineto Backthrust and of the related pop-up structure is coeval with the early Messinian thrusting of the Lepini Mts. thrust sheet upon the geodynamic propagation of the central Apennine chain-foredeep-foreland system.

AbstractMiddle-upper Pliocene wedge-top deposits cropping out near San Mauro Forte village (Basilicata region), along the Southern Apennnines chain-front, unconformably overlie deformed, lower Pliocene deposits and the pre-Pliocene substratum, represented by Cretaceous to Miocene allochtonous units. The middle-upper Pliocene sedimentary succession is markedly transgressive, with deltaic sands and gravels, overlain by shallow-marine to shelfal hybrid arenites (panchine Auctt.) and open-shelf hemipelagic deposits. This sedimentary succession was syndepositionally deformed, as shown by growth strata and progressive unconformities. Different ranks of unconformity surfaces separate hierarchically ordered, informal stratigraphic units. Two main units have been recognised: the lower unit (designated as Sequence 1) is mainly represented by siliciclastic deposits; the upper one (Sequence 2), is made of hybrid arenites and the overlying hemipelagites. Growth strata in the hybrid arenites indicate a strong synsedimentary control of a N-S trending anticline-thrust.
Siliciclastic deposits of Sequence 1 can be ascribed to coarsegrained delta environments, fed by hyperpychnal flows arising from the chain-front and spreading out towards the foreland areas.
Hybrid arenites of Sequence 2 has a mixed carbonate-siliciclastic to pure silicilastic composition and was deposited in storm-driven, shoreface to open-shelf environments. Skeletal grains of Sequence 2 belong to the foramol-type association, in good agreement with other Neogene and Quaternary mixed carbonate-siliciclastic systems of the Mediterranean area. Stratigraphic-sedimentological data suggest that the aforementioned uplift of the anticline-thrust played a leading role in the establishment of favourable conditions for carbonate production. Regional-scale subsidence has brought to the final drowning of these carbonate factories, overwhelmed by hemipelagic sedimentation.

AbstractA geologic survey, integrated with sedimentalogic observations and macrofacies analysis, has been carried out for the Jurassic deposits outcropping in the Mt. Catria-Mt. Acuto area.
The study area is located within the northern Umbria-Marche Apennines and is characterized by the presence of Jurassic different type successions that reflect depositional environment variability.
The aim of this paper is to reconstruct the Jurassic paleographic structural setting and the paleotectonic evolution of the area. Particular attention was given to the characterization of the relationships between deposits formed during and after the drowning of the Calcare Massiccio peritidal carbonate platform. In addition, the depositional trend of this carbonate platform was determined by the characterization of tidal environment sedimentary structures and facies associations.
The data obtained allowed for the identification of two isolated, uplifted blocks of the carbonate platform (Corno di Catria and Mt. Acuto), reduced in size, bounded by escarpments of tectonic origin and separated by a narrow Jurassic basinal area (Mt. Catria). Along paleoslopes of structural highs, drowning Calcare Massiccio "B"-type deposits have been identified that differ from Calcare Massiccio "B" deposited on the tops of paleohighs in their mainly lithoclastic facies. The drowning phase, at the tops as well as along the flanks of the blocks, is also marked by unconformity surfaces (drowning unconformities).
The different paleostructural sectors have been differentiated during the Lias by a phase of strong extensional tectonics that was responsible for the formation of the tectonic escarpments, subsequently affected by submarine erosion.
In the early stages of the Middle Jurassic, tectonic reactivation resulted in formation of some marginal, down-dropped portions of the structural highs, which were subsequently filled by the same cherty sediments that deposited in the Mt. Catria basinal area.
In the study area, the depositional environment has remained differentiated throughout the Jurassic as evidenced by the presence of conformable and unconformable boundaries between the Tithonian calpionellid pelagites of the Maiolica Formation and underlying deposits.

AbstractDuring the Pliocene, along the Apennines front of Southern Italy (Acerenza area), a sector of the wedge-top basin hosted shallow-marine siliciclastic-carbonate (-bioclastic) sedimentation. Sediments consist of mixed arenites and rudites forming an up to 30 m thick unit. Based on the recognition of textural features, sedimentary
structures, and degree of segregation between siliciclastic and bioclastic particles, facies analysis revealed 10 facies grouped into 5 associations. They suggest the occurrence of either wave or current dominated environments, showing different degrees of heterolithic segregation between siliciclastic and bioclastic particles.
The depositional system was characterised by a gentle sloping profile irregularly undulated by syndepositional gentle folds. Waves dominated the shallowest areas of the mixed system and the terrigenous fraction derived mainly from wave erosion of substrate (arenaceous) rocks. These areas were located at the top of anticlines at depths corresponding to that of an upper shoreface sector of a classic coastal profile. The bioclastic fraction derived from the fragmentation
of an in situ heterozoan skeletal-carbonate factory. Almost constant waves activity prevented segregation of the siliciclastic and bioclastic fractions in the lower shoreface zones. In relatively deeper environment of the mixed system (offshore transition), persistent unidirectional currents dominated, with development of tide-influenced 2D and 3D dunes. Repeated oscillations of the water column in the sheltered coastal areas produced modulation of current velocity favouring segregation of the heterolithic fractions along the dune foresets. Finally, in the deepest sector of the system (offshore), pervasive bioturbation dominated causing unsegregation of the siliciclastic and bioclastic fractions.

AbstractWith the aim of estimating the rates of seismic moment and deformation in seismic zones of southern Italy, constraints on tectonic style and kinematics data from geophysical and geologic data were integrated with the traditional constraints from seismicity catalogues.
Seismotectonic considerations indicate that the region can be divided into four broad crustal seismogenic volumes, of relatively homogeneous deformation: an extensional crustal volume in the western part of the Southern Apennines and three crustal volumes characterized by a transcurrent regime in the eastern area.
For each crustal volume, the annual seismic moment release showing the rate of the deformation was estimated by integrating magnitude-frequency relations of historical earthquakes. The application of a Monte Carlo simulation systematically incorporated the uncertainties of the input parameters.
The results show that the westernmost crustal volume is undergoing extension, with velocity of ~1.2 mm/a (along a nearly NE-SW direction), whereas the easternmost volumes are undergoing transcurrent deformation, with an along-strike deformation axis oriented along a nearly E-W direction, with velocities of ~1 mm/a, ~1.2 mm/a and ~0.1 mm/a, respectively for the northern, central and southern volumes.
The errors affecting the estimate of the crustal deformation using the seismicity catalogues may be significant. The parameters with the largest contribution are the coefficients of the magnitudemoment relationship; the second and third contributors are the coefficients of the magnitude-frequency distribution and the maximum magnitude. Uncertainties in the geometrics and kinematics parameters have slight, minor effects. Furthermore, the effects of the crustal model (and the consequent earthquake association) are of the same order as the uncertainties of the parameters involved in the computation.
These results agree with recent GPS data and geological slip rates in terms of direction and rate of deformation.

AbstractThe early to middle Miocene erosive plate boundary preserved in the Northern Apennines NW of the Sillaro Line is formed by two distinct units - the Sestola-Vidiciatico Tectonic Unit and the Subligurian Units. These two units occupy, respectively, the SE and the NW portions of the studied area. Upon closer examination, the features that distinguish these mapped units do not reflect differing plate boundary processes, but rather the incorporation or non-incorporation of forearc-toe mass-wasting deposits into the active subduction channel. In other respects, these two units document similar subduction channel processes, including the contemporaneous activity of multiple sub-parallel slip surfaces. This mode of subduction channel deformation leads to the ‘laminar' incorporation of distinct stacked slices within the channel.

AbstractThe Umbria-Marche Apennines, an arc-shaped fold and thrust belt with eastward convexity and vergence, form the external part of the Northern Apennines. In the middle 1980s, the Umbria-Marche Apennines were interpreted by some as a classical thin-skinned foldthrust belt, with thrust sheets emplaced in an in-sequence, piggyback mode, from the interior to the exterior of the orogen, over a main, basal detachment in the Triassic evaporites. In the mechanics of this kind of edifice, the folds and thrusts would develop within a prism or tapered wedge, bounded at the base by an undeformed basement with a regional monocline dipping toward the hinterland, and at the top by a topographic and structural slope generally dipping toward the foreland. Other authors saw the Umbria-Marche Apennines as a more complex orogen, with basement involvement, possible tectonic inversions, and out-of-sequence thrusts. In the present paper, the geometry, structure, and tectono-sedimentary evolution of the Umbria-Marche Apennines are compared with the classical thin-skinned model. We suggest that this fold-thrust belt can be divided longitudinally into two sectors. The eastern part of the chain, comprising the high Mesozoic carbonate anticlinal ridges of the axial zone together with the Marche external folds, fits the classical model well, but the western part, comprising the Umbrian Pre-Apennines, shows striking differences. The boundary between the eastern and western parts of the Umbria-Marche Apennines is here termed the Scheggia-Foligno Line (SFL). East of this line, the Eastern Umbria-Marche Apennines show an eastward taper between the undeformed basement, dipping gently west, and an upper surface in which both topographic and structural elevation decrease toward the east. West of the Scheggia-Foligno Line, by contrast, seismic reflection profiles and subsurface data show basement involvement in the thrusting at shallow depths, while both the topographic and structural elevations are anomalously low compared to the more easterly parts of the chain. There is also a notable discontinuity in foredeep-basin evolution at the Scheggia-Foligno Line, with welldeveloped foredeep basins in the Umbrian Pre-Apennines and the external Marche belt (the Marnoso-arenacea and Marche Plio-Pleistocene, respectively), whereas only thrust-top basins developed in the axial zone, during the Tortonian-Messinian interval. Various mechanisms, not all mutually exclusive, might be invoked to explain the discontinuity at the Scheggia-Foligno Line. These possible explanations include causes of local character, linked to the sedimentary and tectonic evolution of the region, involving episodic departures from steady-state conditions, interrupting the regular growth of the accretionary wedge. However, it also possible that the Western and Eastern Umbria-Marche Apennines represent completely different orogenic systems, with different causes possibly with the former related to Corsica-Adria collision and the latter due to slab rollback of Adriatic lithosphere. In either case, this study demonstrates the complexity of evolution of the Northern Apennines, with adjacent zones showing abrupt variations in their history and style of deformation, which are difficult to incorporate in a single, unified geodynamic model.

AbstractIntegrated sedimentological and micropalaeontological analyses of Montesecco Clays cropping out along the Molise Apennines foothills allow to reconstruct the depositional setting and major palaeoenvironmental changes within the Molise Periadriatic Basin (Apenninic foredeep) during the Late Pliocene and Early Pleistocene.
Sedimentological and palaeocological data from four reference stratigraphic sections document an overall shallowing-upward tendency within Montesecco Clays, which is also confirmed by compositional data analysis of microfaunal assemblages. Lower Montesecco Clays (Ururi and Trigno sections) accumulated from the middle epibathyal/bathyal to lower circalittoral zone, while upper Montesecco Clays (Guglionesi and Colle Favaro-Petacciato sections) contain a microfauna indicative of an outer circalittoral to infralittoral environment. As documented by previous subsurface data, the palaeoecological analysis suggests increasing depths in the Molise Periadriatic Basin from NW to SE.

AbstractThis work aims at providing an updated and augmented view of present-day tectonics and seismogenic sources of the Abruzzi Apennines, focusing on its extensional domain. This paper was spurred by the 6 April 2009, L'Aquila earthquake (Mw 6.3), an event from which geologists learned important lessons-including rather surprising ones. Although the earthquake was not major compared with other catastrophic events that occurred in Italy and elsewhere, this destructive earthquake led to a thorough review of the geometry - and style, in some instances - that characterises earthquake faulting in this region. The poorly expressed field evidence of the 6 April event, especially in light of the damage it caused in the mesoseismal area, stressed the intrinsic limitation of the earthquake geologists' toolbox.
Abruzzi is the region of a true "seismological paradox": despite the rather long earthquake history available for the region, the number of potential sources for earthquakes of M ≥?6.0 proposed in the literature is two to five times larger than the number of events that appear in the full earthquake record. This circumstance is made even more paradoxical by recent palaeoseismological work that proposed recurrence times of only a few centuries for individual seismogenic
sources. Do the evident faults mapped by previous workers all correspond to potential seismogenic sources?
We aim at addressing this paradox by drawing an updated seismotectonic model of Abruzzi based on the lessons learned following the 2009 earthquake. The model is based on selected geological, geomorphological, seismological, historical and geodetic data and will ultimately feed an updated version of the DISS database (http://diss.rm.ingv.it/diss/).

AbstractWe analyze more than 100 GPS time series of continuous and discontinuous GPS stations located in the Abruzzi region (Italy) surrounding the epicentres of the L'Aquila 2009 seismic sequence. The purpose of this work is to reconstruct the coseismic displacement field caused by the 6th April (Mw 6.3) main shock from a dense network of survey-mode stations surrounding the epicentral area and to characterize the early postseismic deformation field. In the months following the main shock, an extensive GPS survey was carried out on the existing Central Apennines Geodetic Network (CAGeoNet), with the intention of collecting a robust data set and to study the co- and postseismic
deformation field of this Apenninic normal faulting earthquake. The analysis is carried out with two independent procedures and software (Bernese and Gamit) in order to provide reliable and validated geodetic solutions. The analysis of the postseismic transients and the knowledge of long-term inter-seismic velocities at all GPS stations, issued from permanent and CAGeoNet sites, allow us to derive a dense co- and postseismic displacement field for the L'Aquila Mw 6.3 main shock in a wide area around the epicentre. The highest deformation rate occurs during the first 4-5 months after the main shock and persists in the following at slightly slower rate throughout the whole monitoring period. Fast deformation rates imply that most of the observed deformation is due to a process different from a pure viscoelastic relaxation of the stress perturbation. Since the observed rates would imply a too low effective viscosity value (below 1017 Pa s), we rather suggest that most of the observed deformation in the first months after the earthquake is due to different processes, most likely frictional afterslip possibly modulated by the presence of fluids. The new coseismic displacement field is used to invert for the main shock fault geometry, analysing the consistency among the different geodetic solutions and the combined one, with the goal of validating the two data sets.

AbstractField surveys performed by different research groups after the April 6, 2009 L'Aquila earthquake (Mw 6.1; CHIARALUCE et alii, 2011) identified the occurrence of surface faulting along the Paganica normal fault, the causative seismogenic source of the event. The different researchers provided patterns of surface rupture that slightly differ as for the northern and southern portion of the Paganica fault. We here integrated coseismic geodetic data - DInSAR and GPS - with geological observations in order to discriminate what, among the different surface rupture patterns, can be considered as evidence of primary surface faulting. Our results indicated that the Mt. Stabiata-Mt. Castellano faults, to the north, and the San Demetrio fault, to the south - along to which BONCIO et alii (2010) and GALLI et alii (2010) detected ground ruptures, respectively - probably activated solely as sympathetic (sensu SleMMONS & DE POLO, 1986; DE POLO, 1994) tectonic structures during the 2009 earthquake. These observations allowed to constrain the extension of the primary surface faulting from the Collebrincioni sector to the area of San Gregorio, thus representing the northern and the southern tips of the Paganica fault, respectively. This defines a total surface rupture length of 12-13 km. Our results highlight the effectiveness of entwining geological and geodetic data to discriminate primary surface faulting from secondary fault ruptures, particularly in cases of moderate magnitude earthquakes, i.e. when modest and rather subtle surface faulting can occur.

AbstractWe present high-resolution Vp models of the Middle Aterno basin obtained by multi-scale non-linear controlled-source tomography.
Seismic data have been collected along four dense wide-aperture profiles, that run SW-NE for a total length of ~6 km in the hangingwall of the Paganica-S. Demetrio Fault, source of the 6th April 2009 (Mw 6.3) L'Aquila normal-faulting earthquake. Seismic tomography expands the knowledge of the basin with high spatial resolution and depth penetration (>300 m), illuminating the Meso-Cenozoic substratum that corresponds to high-Vp regions (Vp>3500-4000 m/s).
Low Vp (1500-2000 m/s) lacustrine sediments (Early Pleistocene in age) are imaged only in the SW sector of the basin, where they are up to 200 m thick and lie below coarse fluvial and alluvial fan deposits. The overall infill consists of Early Pleistocene to Holocene alluvial fan and fluvial sediments between the Paganica Fault and the Bazzano ridge, with Vp reaching 3000 m/s for the oldest conglomeratic bodies. The substratum has an articulated topography. The main depocenter, ~350 m deep, is in the SW sector of the basin south of the Bazzano ridge. Remarkably, this depocenter and the overlying thick lacustrine body match the area of maximum coseismic subsidence observed after the 2009 earthquake. In the Paganica area, Vp images unravel large steps in the substratum related to two unreported SW-dipping buried strands, synthetic to the Paganica Fault, with ~250 m associated total vertical throw. This finding has important implications on the long-term history of the Paganica-S. Demetrio Fault system, whose total vertical displacement has been previously underestimated. An additional ~250 m vertical offset along this complex Quaternary extensional structure should therefore be considered.

AbstractCarbonate platforms bordering the Tethyan margins carry a distinct periodic signal that can be related to Jurassic-Cretaceous climate and eustatism. They yield a rich archive of information, including the tectonics affecting the platforms at regional (subsidence) as well as at «local» (uplift) scale, at a time scale between 104 and 105/106 years (order of magnitude). In Central and Southern Italy, we have analyzed at centimetre scale, along well exposed sections and in bore cores, textures and early diagenetic features of Cretaceous carbonate platform deposits that evidence oscillations in which a hierarchy of cycles (elementary cycles, bundles and super bundles) has been recognized. Eustatic-climatic, high-frequency changes, linked to the Earth's orbital perturbations, have been considered at the origin of this hierarchy, where the elementary cycles record the precession and/or the obliquity periodicities,
while the bundles and super bundles record the short- and long-eccentricity, respectively. These orbital cycles are, in turn, superimposed on lower-frequency cycles (Trangressive/Regressive Facies Trends, T/RFTs).
Adopting a sequence stratigraphy approach, the super bundles and the T/RFTs have been interpreted in terms of depositional sequences and used for high-resolution, long-distance (regional to supraregional) correlation, as well as for assembling orbital chronostratigraphic diagrams which quantify the minimum time required for each succession
to stack up. Moreover, we have observed that a number of gaps are randomly intercalated in the various sections so that the high-precision correlation of distant intervals rises the problem of explaining their local absence. To reconcile these discrepancies, we propose a tectonic mechanism, already used to explain the stratigraphic gaps related to bauxitic horizons intercalated up section in the same stratal successions. Namely we postulate that the action of transient lithospheric bulges (few meters to tens of meters in elevation, few to several tens of kilometres across),
arising from distant compressional or extensional tectonics, may give an explanation for the stratigraphic architecture characterizing the cyclic organization of the lower Cretaceous shallow-water carbonates.
In conclusion, we assume that while the eustatic oscillations, driven by orbital and allied climatic variations, follow high-frequency composite rhythms of few tens to few thousand years (Milankovitch periodicities), the regularity of the subsidence is locally modified by transient lithospheric bulges, that result in increase (lows) and decrease (ups) of subsidence (and hence variation of rate of sediment deposited), up to the emersion of more or less large areas evidenced by omission of strata as well as by paleokarst and bauxites.

AbstractNew biostratigraphic data from two stratigraphic sections (Mt. St. Enoc and Mt. Volturino), of the Lagonegro Basin (Southern Apennines, Italy), define the age of the sedimentary events and delineate the sedimentary evolution for the Norian-Rhaetian time interval.
The upper part of the Calcari con Selce Fm in the Mt. St. Enoc section is characterized by an alternation of cherty limestones rich in organic matter and thin silicified calcarenites with black cherty layers. The upper part of the Calcari con Selce Fm of the Mt. Volturino section exhibits instead intermediate characters between the Calcari con Selce and Scisti Silicei Fms, with cherty limestones, shales and radiolaritic beds. The biostratigraphic data based on conodonts and radiolarians allowed a good correlation among the Norian-Rhaetian successions throughout the Lagonegro Basin the two sections represent two different environments of the Lagonegro Basin. In fact, radiolarites (Scisti Silicei Fm) are present from the Misikella hernsteini-Parvigondolella andrusovi conodont Zone (late Sevatian) in the Mt. Volturino section while they appeared after the Misikella ultima conodont Zone (uppermost Rhaetian) in the Mt. St. Enoc section. This proves that euxinic carbonate facies and radiolaritic facies were deposited in the same time interval and in the same basin. On the basis of sedimentological analysis and with the support of biostratigraphy, the non-coeval beginning of biosiliceous sedimentation is discussed in order to point out the control factors: different paleobatimetry, upwelling areas or volcanic activity. Our preliminary results show that the Lagonegro Basin during the Norian-Rhaetian interval was probably characterized by an articulated physiography and that volcanism should have had an important role in changing pelagic sedimentation.

AbstractIn this paper we describe the geometry and kinematics of a contractional structure, consisting of a thrust and related minor structures, which doubled the Tuscan Nappe cropping out in the southern side of the Monte Amiata geothermal region (Selvena-Castell'Azzara area), during the building of the Northern Apennines. Such a thrust (hereafter the Monte Penna thrust, MPT) is documented, in this area, for the first time. The integration of fieldwork with mine data from two different cinnabar/stibnite mines helped us to better define the thrust geometrical setting both at the surface and underground.
Thrusting took place during the Early Miocene and produced the tectonic repetition of the Tuscan Nappe succession. The thrust gave rise to two tectonic subunits (SU1 and SU2) separated by a contractional shear zone up to 3m thick. Such a shear zone consists of three structural domains characterised by different structures such as folds, a tectonic foliation, reverse faults and Riedel shear fractures. They indicate a top-to-the ESE sense of shear, coherently with the general staking pattern of the Northern Apennines belt at least for the study area and surroundings.
The thrust-sheet was deformed by cartographic- to mesoscopic folds, N135° to N220° striking on average, NE- and SE-verging, respectively. The tectonic setting recognised in the study area is coherent with that of the Tuscan Nappe described for the Monte Amiata region and the whole southern Tuscany, resulting characterized by duplex system. Such a duplex system was affected by extensional structures since the Middle Miocene. Presently, the thrusts consist of relic structures preserved within extensional horses. The whole evidence possibly make the Tuscan Nappe duplex system comparable with the structure of the Tuscan Metamorphic «basement», in terms of geometry, stacking pattern and timing, suggesting a probable common structural evolution even if a different structural levels.

AbstractAmong the many cases studied of mass-transport deposits in continental margins, the role of basin topography in controlling the types, distribution, architecture and emplacement of such deposits has not been properly remarked.
In the western portion of Northern Apennine foothills, masstransport deposits form two composite Messinian mass-wasting bodies that reveal progressive development strictly controlled by basin topography. Extensively analyzed through stratigraphic and structural studies, they form two major elliptical-shaped bodies in map view; maximum 10 kilometres wide, tens of kilometres in length and with estimated volumes of about 250 km3 each, they are elongated parallel to NW-SE oriented thrust fronts. They are coalescing chaotic masses that consist, at the base, of debris flows formed by monogenic gypsum arenite or breccia and decametric blocks of primary gypsum, whereas at the top they are made up of kilometres-wide outliers of pre-gyspum deposits, which slid away from partially preserved headwall scarps. In the external accumulation zone, the mass wasted deposits show imbricate thrust-stacks composed of scraped-off gypsum debris flow deposits. The types, distribution, architecture and emplacement of the studied mass-transport deposits testify the strict control of the wedge-top basins morphology. The internal and steeper flank of the wedge-top basins was representing the depletion zone of sliding masses; whereas, the outer and less steep flank of the wedge-top basins stopped the moving masses and formed the accumulation zones. The relief of the wedge-top basins was progressively modifying during the intra-Messinian tectonic pulse that, affecting the entire Northern Apennine orogenic wedge, triggered the studied mass-transport deposits.

AbstractThis paper deals with a structural and petrographic study carried out on key outcrops belonging to the Tuscan Nappe exposed in the Colline Metallifere region (Montieri-Poggio Prugnoli). Here, the Tuscan Nappe was affected by polyphase deformation characterized by superposed folding events (F1, F2 and F3) and related tectonic foliations (S1 and S2) in agreement with the structural setting described for the Tuscan Nappe exposed both in other places of southern Tuscany, and in the Alpi Apuane region. The development of F1 folds was accompanied by metamorphism which produced a sin-kinematic mineralogical assemblage developed on the S1 tectonic foliation. This paragenesis, consisting of calcite + quartz ± muscovite ± Fe- and Ti-oxides, is indicative for a temperature of about 200-300°C according to the T values estimated for the F1 folding event documented for the Tuscan Nappe of the Apuan Alps, suggesting a very low grade metamorphism which affected the Tuscan Nappe during its stacking in the Northern Apennines collisional belt.

AbstractThe impact on the territory of important archaeological sites and related human activities has induced, as a rule, modifications in the local environmental system. An example is represented by the sanctuary of the goddess Mefitis in Macchia Rossano, in the territory of Vaglio Basilicata, close to the town of Potenza (southern Italy). This archaeological site has been affected by swelling in historical times that occurred in the allochthonous, chaotic, heterogeneous, and anisotropic polychrome scaly clays of the geological formation called Argille Varicolori. In such structural conditions, the collapse mechanisms of the Argille Varicolori seem to be strongly influenced by pre-failure phenomena and, therefore, the application of the limit equilibrium method does not always seem to be suitable. Nonetheless, the analysis in terms of total stress and the in situ assessment of the relationship between rainfall and fluctuations of the groundwater level by long-term monitoring have allowed to determine the amount of rainfall related to the piezometric level of collapse and, consequently, to assess the conditions of the sanctuary in the historical times when the landslides occurred.

AbstractSeismic and outcrop data suggest that the Mesozoic carbonate successions cropping out in the Matese and Camposauro Groups, in the central-southern Apennines of peninsular Italy, can be interpreted as an exposed part of the Inner Apulia Platform (PAI). Cretaceous sequences have been studied in detail in the field and compared with the coeval carbonate sediments of the Inner Apulia Unit cored in the Benevento oilfield and in the Monte Taburno 1 and Morcone 1bis wells. Subsurface data show that, starting from the late Aptian time onwards, the Inner Apulia Platform was dismembered into a series of sub-domains which included shelfal productive areas and a series of small intra-platform basins (or elongated depressions). These basins have a mean Apennine orientation and were locally affected by significant subsidence.

Outcrop analyses indicate similar tectono-sedimentary trends and led to the recognition of three main structuring phases, that can be ascribed Middle Aptian, Late Aptian-Albian and Early-Middle Cenomanian time intervals, respectively. The main structural features, formed during the first structuring phase, were repeatedly reactivated during the subsequent phases and controlled the palaeo-environmental evolution of the various sub-domains, that were characterised by different facies and facies associations.

The facies analysis from integrated outcrop and core data shows analogous evolutionary trends. In particular, starting from the middle-late Aptian, the carbonate factories display a sharp variation in the sedimentary dynamics and depositional architectures: the uniform pre-Aptian shallow-lagoon rimmed system rapidly evolved into a much complex system in which shallow-water rudist-dominated carbonate factories were located alongside by-pass and deeper basinal areas. At outcrop, the steering toward open marine conditions can be correlated with the early (middle Aptian) structuring phase of the platform. This trend is marked in the easternmost studied areas by the formation of tectonically active margins, characterised by the presence of complex channel networks, but is also evident in the innermost sectors (western areas) of the shelves, by the increase in frequency and intensity of high-energy events.

The varied time-span of the «mid-Cretaceous» stratigraphic gaps (see CARANNANTE et alii, 1987, 1994; RUBERTI, 1992) supports the hypothesis of a complex tectonically-controlled palaeo-topography and of a differential evolution of the related sub-domains. Since the late Turonian, a shallow sea encroached on the exposed lands. Deposition of shallow water rudist-rich sediments followed. The peculiar features of the benthic assemblages which dwelled patchily in loose substrata resulted in the lack of real reefs at the shelf margins. This enhanced the water circulation and controlled the 3D arrangement of the sedimentary bodies made up mainly of large coalescing sheets of winnowed fine to coarse skeletal sands. The skeletal fraction, produced by intensive bio-erosive and mechanical processes acting on mainly diagenetically stable calcite-shelled organisms, covered most of the open shelf. This large amount of loose silt- to pebble-sized bio-clastic debris was periodically removed from the shelf, transported (often through submarine channels) and re-sedimented in the adjacent strongly subsiding intra-platform basins formed during the Lower Cretaceous and Cenomanian structuring phases.

Finally, the study of available seismic lines allowed for correlation between the Matese Mountains and the Morcone 1 well and the Benevento oilfield. These lines, tied to well data, show a complex structure formed by several thrusts where older units pertaining to the Apulia Platform are piled up over younger siliciclastic units of the Miocene Foredeep. Further, the foredeep siliciclastic deposits are as old as lower-middle Tortonian in the Eastern Matese, while as young as late Tortonian in the Morcone 1 well and Pliocene in the Benevento oilfield. This remarkable time-polarity appears to support the hypothesis presented in this contribution, and makes it possible to constrain the timing of the thrust emplacement for this sector of the Apennine Chain.

AbstractThe southern Apennine is the segment of the circum-Mediterranean orogenic system between the central Apennine to the North and the Calabria-Peloritani arc to the South, bounded by the Ortona-Roccamonfina and the Sangineto tectonic lines respectively. It consists in a salient north-east verging thrust and fold belt, interposed between the back-arc Tyrrhenian basin to the West and the undeformed Apulian-Adriatic foreland to the East. Its present structural setting is the result both of mainly compressive tectonic events, related to the subduction followed by the roll-back of the Adria plate, and of the extensional tectonics related to the opening, since the late Miocene, of the Tyrrhenian sea (MALINVERNO & RYAN, 1986; PATACCA & SCANDONE, 1989; DOGLIONI, 1991). Aiming to point out the space-time migration of the deformation, a geological map of the area between the Ortona-Roccamonfina tectonic line to the North and the Maratea-Val d'Agri alignment to the South showing the possible kinematic units of the southern Apennine has been elaborated. The above area includes the whole Campania and part, of Lucania, Molise and Puglia regions. A kinematic unit can be defined as a stack of tectonic units (or even only one), eventually covered with thrust top deposits, that piled up during the same tectonic event and afterwards behaved like an unique geological body in respect to more external areas.

In the frame of the regional geological setting, some well established sedimentologic and stratigraphic characteristics have been assumed as reference criteria for grouping together some tectonic units in a kinematic unit: (i) the beginning and the gradual increase up to prevail of the immature siliciclastic sedimentation marks the depocentral phase in the evolution of a foredeep basin; (ii) the fore-deep deposits rest conformably on the older successions, as the angular unconformity due to the progressive flexuration of the foreland is not appreciable at a local scale; (iii) the compressive tectonic event, immediately following the foredeep stage, involves a wide portion of the flexured foreland, that is accreted to the nappe stack of the chain. In each tectonic unit this tectonic event is chronologically constrained between the age of its conformable foredeep deposits and by the age of the unconformable thrust-top deposits sealing the contacts among different tectonic units. However this simple relationships may be masked by later compressive and extensional tectonic events, as well as by transcurrent tectonics. The possible presence of younger deposits resting unconformable on the already deformed substratum and related thrust top deposits is a constraint to the age of these later tectonic events. The map has been elaborated tacking into account, besides the numerous and sometimes contrasting data of the literature, even data, often still unpublished, from the surveying of the new geologic map of Italy 1:50.000. The kinematic units, marked with capital letters (A to G from the older to the younger) group together tectonic units, derived from paleogeographic domains that have been affected by the first tectogenetic event in the same chronological interval. In each kinematic unit with lower case have been distinguished: a) the pre-orogenic succession; b) the foredeep stage deposits; c, d) the thrust-top basin deposits. The kinematic unit A includes several tectonic units (Liguride and Sicilide Complexes Auct.), mostly ocean derived, piled up to form accretionary wedge during the Early Miocene, following the closure of an oceanic branch (Lucanian Ocean) of the Neothetys realm. It is subdivided into: a) Jurassic to Aquitanian pre-orogenic successions (the ophiolite basement of some of them crops only SE of the mapped area); b) the Aquitanian-Burdigalian foredeep deposits; c) the upper Burdigalian/Langhian - Serravallian thrust-top deposits (Cilento Group, AMORE et alii, 1988; BONARDI et alii, 1988b; AMORE et alii, 2005); d) the Tortonian further thrust-top deposits. The kinematic unit B groups the units of the chain involved by the orogenic transport during the Serravallian-lower Tortonian. It is formed by: a) the upper Triassic-lower Miocene pre-orogenic successions, of the M. Bulgheria SCANDONE et alii, 1964) and Alburno-Cervati Units (SCANDONE, 1972; BONARDI et alii, 1988a); b) the Langhian foredeep deposits; c) the middle-upper Tortonian thrust-top deposits. The kinematic unit C groups the units of the chain involved by the orogenic transport during the lower-middle Tortonian; in particular they are distinguished in: a) the upper Trias-Langhian pre-orogenic successions, forming the Picentini-Penisola sorrentina, Taburno-M. Marzano-Monti della Maddalena and the Capri-M. Monna-M. Foraporta Units (BONARDI et alii, 1988a; SGROSSO, 1998); b) the Serravallian foredeep deposits; c) the middle-upper (?) Tortonian thrust-top deposits. The kinematic unit D groups the units of the chain involved by the orogenic transport during the middle-upper Tortonian; in particular they are distinguished in: a) the lower Triassic-Langhian pre-orogenic succession belonging to Lagonegro II-Frigento Unit (SCANDONE, 1967, 1972; DI NOCERA et alii, 2002) and to Monte Croce Unit (Scandone & Sgrosso, 1974) and that upper Triassic-Cretaceous of the «Lagonegro I» Unit (Scandone, 1967, 1972); b) the Serravallian-lower Tortonian foredeep deposits; c) the upper Tortonian thrust-top deposits; d) the upper Tortonian-lower Messinian further thrust-top deposits. The kinematic unit E groups the units of the chain involved by the orogenic transport between the upper Tortonian and the lower Messinian; in particular in this unit are distinguished: a) the Trias-middle Tortonian pre-orogenic successions, referred to the Matese-M. Maggiore-M. Camposauro Unit (BONARDI et alii, 1988a; SGROSSO, 1998); b) the middle-upper Tortonian foredeep deposits; c) the lower Messinian thrust-top deposits; d) the upper Messinian further thrust-top deposits. The kinematic unit F groups the units of the chain involved by the orogenic transport during the upper Messinian; in this unit are distinguished: a) the Lias-lower Messinian pre-orogenic successions of the north-western Matese Unit (SGROSSO, 1996, 1998), the Frosolone Unit (SELLI, 1957) and the Daunia Unit (Dazzaro et alii, 1988); b) the Messinian foredeep deposits; c) the upper Messinian -lowermost Pliocene thrust-top deposits. The kinematic unit G groups the units of the chain involved by the orogenic transport during the upper? part of the lower Pliocene; in this unit are distinguished: a) the Tortonian-Messinian pre-orogenic successions of the Vallone del Toro Unit (BASSO et alii, 2002); foredeep deposits are not recognizable; c) thrust-top deposits of the upper part of the lower Pliocene; d) the middle-upper Pliocene further thrust-top deposits. In several tectonic units, elements useful to establish the age of the first deformation, i.e. the foredeep siliciclastic deposits or the immediately following unconformable deposits, are missing, therefore their inclusion in one or another of the kinematic units is matter of debate. Also in this case the geometrical position and the regional framework can be used to formulate reliable hypotheses. The map is aimed to focalize the main open problems and stimulate the discussion about them. The analysis of the areal distribution of the kinematic units leads to some general considerations. On a small scale an irregular spatial distribution of the kinematic units is recognized. In the segment of chain represented by the map, the more internal tectonic units widely outcrop in the south-eastern sector and are missing northward even on the Tyrrhenian side. On the contrary the more external units, crop out only in the north-western sector, whereas in the south-eastern one they have not been recognized even by sub-surface data. This irregularity could be linked to original paleogeographic irregularities or even be the result of Plio-Pleistocene second order archings and of transcurrent faults that cut transversally the chain, but geodynamic causes still not clarified cannot be excluded. The elaboration of a kinematic map is an essential but not sufficient step for the palaeogeographic reconstructions that need further data and informations on the distribution of the units at depth. The difficulty in the palaeogeografic reconstructions is also due to the fact that the chain is at present constituted only by a few and unevenly distributed fragments of the original domains.

AbstractThe Central Apennines consist of a fold and thrust belt developed during the Neogene, involving sedimentary successions of different paleogeographic domains. The geodynamic evolution of this sector of the chain was controlled by several important tectonic events, highlighted by numerous depositional sequences recognized in the Neogene marine successions. Time-scanning of the stratigraphic events has allowed us to reconstruct: the different stages of the eastward shift of the chain-foredeep-foreland system; the deformation chronology; the recent effects of the interactions between the regional uplift and extensional tectonics in the chain and the progressive eastward tilting of the Periadriatic domain. During the Miocene-Early Pliocene interval the Tyrrhenian area constituted a remarkable topographic swell, linked to an upwelling mantle dome. As a consequence, intense erosional processes developed on this area, together with crustal delamination and lateral gravitational spreading. The Tyrrhenian-derived siliciclastic detritus fed the Apennine foredeep and thrust-top basins; the continuous asthenospheric uplift in the Tyrrhenian margin favoured the formation of axial crest grabens, crust delamination and the emplacement of a stack of gravitational nappes in the Apennine sector. The maximum uplift of the mantle doming was recorded at the beginning of the Upper Messinian. The remarkable uplift of several asthenospheric domes, located in the Mediterranean area, favoured the closing of the sea-ways, connecting the Atlantic with Peri-mediterranean basins. Consequently the salinity crisis developed, with a relative diachrony: the evaporites sedimented at first in the crestal areas and later in the deep ones. The marine episodes recognized in the lago-mare sediments represent the end of uplift processes and a progressive dome deflation with sporadic connections with the Atlantic. During the Middle Pliocene-Quaternary, the intense thinning of the Tyrrhenian crust induced the collapse of the axial dome and subsidence of the rift belt.

AbstractResolving tectono-stratigraphic relationships, critical for using syn-tectonic sedimentation to calibrate time and length scales of processes in the Apennine-Maghrebian orogenic system, is difficult using outcrop data alone. Here two commercially-acquired seismic reflection profiles are used to establish the structure and stratigraphic relationships between the frontal part of the orogenic belt, the foredeep and foreland regions in the offshore continuation of the Apennine system in the northern Ionian sea. Seismic stratigraphic reasoning is used to define an inter-regional intra-Messinian unconformity surface. In the Apulian foreland this is cut by a widespread array of normal faults that are sealed by Plio-Quaternary sediments. The modern foredeep is in part controlled by these faults. On the Apulian shelf the deposystems are broad. However, the modern foredeep and basins developed on the orogenic wedge are only a few km across. Given the proximity of this study area, the tectono-stratigraphic relationships imaged on these seismic lines are likely to provide good analogues for Neogene basins and depositional systems for much of the Apennines onshore. Syntectonic basins are narrow, long-range stratigraphic continuity is likely to be the exception rather than the rule. This challenges some of the assumptions behind existing tectonic models for the Apennines and similar orogens.
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AbstractA new proposal attempting to solve the long-debated issue of the polarity of subduction in the Corsica-Northern Apennine system is presented. Models adopting an original W-dipping subduction and models preferring a flip in the polariy of subduction, from E-dipping to W-dipping, encounter major difficulties at a regional scale. It is considered here that the main inconsistencies faced by both models are due to the two-dimensional approach of reconstructions. The Late Cretaceous to Present-Day kinematics of the Central Mediterranean has been reconstructed using the magnetic anomalies in the Atlantic Ocean and assuming a solid connection between Africa and Adria. Oligocene to Present calcalkaline volcanism and backarc extension in the Balearic and Tyrrhenian basins requires the presence of a wide oceanic embayment to the west of the Adriatic Promontory. It follows that the continental collision that gave rise to the Alps s.s. could not continue SW-ward of Adria. The flip of subduction polarity that can be currently observed, going from the Alps, where Africa is overriding Europe, to the Apennines, where the opposite occurs, was likely on original feature since the beginning of convergence. Kinematic reconstructions allow the point along the plate boundary where the flip of polarity occurs to be tracked back in time. Following the N-ward motion of the colliding Adriatic Promontory, the point of polarity flip moved along the plate boundary from Late Cretaceous to Eocene. As a result, areas that previously experienced continental collision were subsequently affected by oceanic subduction. This sequence of events led to the collapse of the Alpine belt of Corsica and to the opening of the Balearic backarc basin above a retreating oceanic subduction. A similar kinematic evolution is currently ongoing in Taiwan. Finally, the Northern Tyrrhenian basin opened when delamination affected the Adriatic continental margin, following the consumption of oceanic lithosphere at the end of Corsica-Sardinia rotation.

AbstractIn the Trasimeno Lake area (Umbria Region), several thrust sheets belonging to the Sansepolcro-Monte Filoncio and Rentella Units, are interposed between the Tuscan Nappe (in the hanging-wall) and the Umbria-Romagna Unit (in the footwall). The thrust sheets succession of the Sansepolcro-Monte Filoncio Unit is made up of Rupelian-Chattian Scaglia toscana Fm. and Chattian-Aquitanian foredeep deposits of Macigno Fm.; the base of the siliciclastic succession becomes gradually younger eastward. The compositional mode of the fine-grained rock fragments in the arenaceous turbidites is comparable with that of the upper part of the Macigno Fm. in the Tuscan Nappe.

The succession of the Rentella Unit includes Rupelian-Aquitanian Monte Rentella Fm. and Aquitanian-Burdigalian foredeep siliciclastic turbidites of the Montagnaccia Fm.. In the lower portion of the Montagnaccia Fm. a level of black cherty horizons is present, as detected in all Aquitanian-Burdigalian successions of the Northern Apennines. The compositional mode of the fine-grained rock fragments in the turbidites is comparable with that of Marnoso-Arenacea Fm..

All these data allow an Oligocene-Miocene paleogeographic reconstruction of the Northern Apennines foredeep. Based on the age, the compositional mode and structural position, the Rentella and Sansepolcro-Monte Filoncio Units can be compared to the Carigiola and Acquerino Units cropping out in the Tuscan-Emilian Apennines.

AbstractWe analyse the instrumental seismicity of the Abruzzo region in the period 1981-2003 in order to obtain a catalogue as homogeneous as possible in terms of location procedure and quality of the results. We analyse four temporal datasets: 1981-1991; 1992-1996; 1997-1999 and 2000-2003. The 1981-1991 dataset is taken from the CSTI catalogue, opportunely selected by using quality criteria. The datasets from 1992 to 2003 are relocated by integrating the recordings of the national seismic network with the recordings of the local Abruzzo seismic network (operating from 1992 to 1999). Particular attention is paid to the velocity models, in order to account for the different stratigraphic/tectonic domains which characterize the Abruzzo region. In particular, we used 8 velocity models, applied to stations or groups of stations lying within relatively homogeneous areas. We obtained a database, selected for RMS ≤0.5s and hypocentral errors ≤5 km, of 985 events with 0.5≤M≤4.4 plus two events of moderate magnitude (Mw=5.9, Mw=5.5) corresponding to the largest shocks of the May 1984 Sangro Valley seismic sequence. We also computed 17 new focal mechanisms. The seismotectonic implications mainly concern the thickness of the seismogenic layer. A robust statistical estimate of the base of the seismogenic layer is given by the depth above which the 90% of seismicity occurs (D90). The maximum thickness (15-17 km) is found in the eastern Abruzzo Apennines (surface heat flow ≤40 mW/m2). A thickness of 12-14 km is found in the western Abruzzo Apennines (40< surface heat flow ≤60 mW/m2). The observed depths are consistent with independent rheological data (B-D transition). The connection between the background seismicity and the geometry at depth of the active faults is feasible only rarely (e.g. M. Gorzano normal fault in northern Abruzzo). More often the seismicity is spread within the seismogenic volume. Locally, it concentrates close to structural complexities or defines small seismic sequences activating inherited structures. The active faults south of L'Aquila are almost free from microseismic activity. The new focal mechanisms computed from the 1992-1999 database confirm and reinforce the existence of a dominating extensional regime across the Abruzzo Apennines.

Abstractn the frontal sector of the Central-Southern Apennines, surface geological data integrated with seismic line interpretation provide new constraints into the reconstruction of the structural inheritance of Mesozoic pre-orogenic and Messinian-Pliocene syn-orogenic normal faults on the salient geometry of the Pliocene-Quaternary thrust system.

In the Umbria-Marche-Abruzzi area, pre-orogenic normal faults commonly juxtapose the complete Jurassic succession (about 900 metres in thickness) onto coeval condensed successions (about 50 metres in thickness) deposited over structural highs. In the Sibillini Mts and Gran Sasso area, pre-orogenic normal faults are truncated and rotated into Pliocene thrust-sheets according to simple short-cut trajectories. In particular the foreland-dipping Jurassic normal faults in the Sibillini Mts area have been rotated and reactivated during the thrust propagation forming high-angle blind-thrusts in the east verging overturned folds.

The Maiella anticline, which involves the Mesozoic-Miocene Apulian carbonate succession and the related slope deposits, joins the Central Apennine fold-and-thrust system to the Apulian Chain buried below the allochthonous Units of the Southern Apennines. Seismic line interpretation allowed us to reconstruct the three-dimensional pattern of the Apulian thrusts, oriented N-S, NNW-SSE and E-W, that are parallel to normal faults related to the Pliocene-Quaternary flexural extension in the foreland. Detailed reconstruction of the Setteporte and Monte Taburno structures shows main N-S/NNE-SSW trending thrusts, branching into NW-SE/E-W trending minor thrusts and back-thrusts, characterized by push-up geometry, typically referable to a transpressive deformation and/or to the positive reactivation of normal faults. Moreover, the sharp westward deepening of the base of the Apulian sedimentary succession (from 4.5 to 6.0 sec in TWT), based on the interpretation of the CROP 11 seismic reflection profile, and the concomitant increase in thickness of the Triassic sequence along the Maiella-Casoli transect, suggest the existence of west-dipping (?)Permian-Triassic normal faults that strongly controlled the distribution and thickness variation of syn-rifting sediments. An inversion of the deepest low angle portions of the pre- and syn-orogenic normal faults is in agreement with surface data (i.e., the structural elevation of the carbonate succession in the Casoli-Bomba anticline) and seismic line interpretation (i.e., deep seated location of the base of Apulian sedimentary succession below the same anticline).

In the reconstructed inversion tectonics model, the N-S trending pre-thrusting normal faults are fully inverted as N-S transpressive segments of the salient structures of the chain, whereas, the NW-SE trending thrusts inverted the low angle portion of pre-thrusting normal faults in the middle-lower crust and displaced with a short-cut the normal faults in the upper portion of the crust. As a result, the pattern of the pre-existing normal faults is inherited on the salient structures of the Central and Southern Apennine Chain.

AbstractIn the Northern Apennines, the Poggio Carnaio Sandstone Formation consists of sandy-clayey turbidites, cropping out in the northernmost corner of the Val Marecchia Nappe.

The formation has been considered Oligocene in age and is commonly interpreted as an Epiligurian unit, unconformably deposited above the Val Marecchia Nappe during its transport towards the Adriatic foreland.

The Poggio Carnaio Sandstone Fm rests on the Argille Varicolori Fm of the Val Marecchia Nappe, but field data do not allow it to be recognized wherever it abruptly replaces the pelagic sediments of the Argille Varicolori Fm, thus testifying to the foredeep evolution of the basin, or where it unconformably overlies this latter formation.

Nannofossil assemblages are characterized by abundant reworked Cretaceous and Paleogene taxa and by some taxa, whose first occurrence is reported in the upper part of the NN4 Zone = upper part of the CN3 Zone. Therefore the formation must be considered not older than Langhian.

Detrital modes of arenites revealed a quartz-feldspathic composition and the lithic component includes mainly metamorphic fragments and minor plutonic, sedimentary, ophiolithic and volcanic clasts. The presence of clasts of garnet, sillimanite, hornblende and glaucophane is significant. Biostratigraphic as well as petrographic data agree with the interpretation of the Poggio Carnaio Sandstone Fm as an Epiligurian succession.

Rock fragments indicate source areas characterized by Ligurian-, Pennidic- and Australpine-type units. Sedimentary facies and textural features of arenites, revealing a rapid erosion and deposition of clasts in a basin close to the source area of the clastic supply, indicate that the Alps cannot be considered as the source area of these arenites, as frequently argued for many North-Apennine clastic formations. Ligurian-, Pennidic- and Australpine-type units were located close to the Poggio Carnaio Sandstone basin, probably representing the geometrically highest units of the Palaeo-Apennine Chain.

AbstractGeological mapping, combined with macroscopic and microscopic structural analyses have been used to unravel the geometry and tectonic evolution of the Monti dell'Uccellina group (Southern Tuscany). A polyphase tectonic history has been recognized, characterized by three main tectonic events associated with the development of shear zones, folds and foliations. During the first tectonic phase, East verging F1 folds with axial plane foliation developed under very low-grade metamorphic conditions, as highlighted by illite crystallinity data and by the calcite-dolomite geothermometer.

Several piled tectonic units, belonging to the Tuscan and Subligurian domains, constitute the backbone of the Monti dell'Uccellina range.

These are, from bottom to top: 1) the Torre Cannelle Unit, made up by the Verrucano Group rocks; 2) the Talamone Unit, made up by the Calcare Cavernoso Formation; 3) the Monti dell'Uccellina Unit, represented by a passive margin sequence spanning from the Triassic Verrucano group at the base to the Tertiary Scaglia Fm. at the top; 4) the Vacchereccia Unit, represented only by Triassic Verrucano Group; 5) the Collelungo Unit, made up by the Calcare Nummulitico Fm. followed by the Macigno Fm; 6) the Canetolo Unit (Sub-Ligurian Unit Auctt.) represented by the «Argille & Calcari» Fm.

Stacking of the nappe pile occurred during the first tectonic phase (D1) in two stages: during the first stage the main tectonic units were emplaced. The second tectonic stage is characterized by later thrusts that cut through the older ones, all of them with a top-to-the- East sense of movement, that led to the emplacement of three tectonic complexes. Each complex comprises three superposed tectonic units that are from top to bottom the Collelungo Unit, the Vacchereccia Unit and the Monti dell'Uccellina Unit.

During the second tectonic phase (D2), the nappe pile was deformed by a kilometre-scale N-S trending upright antiform gently plunging towards the North.

The last tectonic phase is characterized by the development of sub-horizontal folds and of low-angle detachment faults that were produced during the post-collisional extensional events.

A detailed survey, that was achieved through compilation of a 1:10.000 scale map, has clarified the structural and stratigraphic position of the «Pseudoverrucano» Auctt. Formation, whose attribution has been debated for a long time. According to our data it can be referred to two different tectonic units: the Vacchereccia Unit, represented only by this formation, and the Monti dell'Uccellina Unit where it constitutes the bottom of a post-Triassic continental margin sequence.

AbstractGeological mapping and structural analysis carried out in the Sannio-Molise sector of the Southern Apennines provide a complete record of the polyphase deformation sequence affecting the succession of the Daunia Unit. These deposits represent an ancient foredeep turbiditic succession, deposited from Oligocene to upper Tortonian and involved in the Apennine tectonics since upper Tortonian times.

Two main contractional stages can be distinguished in the structural evolution of the Daunia Unit: the first deformation stage, which consists of initial layer-parallel-shortening and in the development of thrusts and metre- to decametre-scale wavelength folds (F1 and F2) developed in an extremely short time, between the upper Tortonian and pre-salinity crisis Messinian. The timing of this first deformation phase is well constrained by the presence of thrust-top Messinian-Pliocene deposits extensively outcropping in the studied area.

The second stage of the contractional deformation is characterized by gentle folds with sub-vertical axial surfaces (F3), metre- to hectometre-scale in wavelength, and breaching thrusts, active at least until the middle Pliocene.

Finally, the Daunia Unit has been affected by extensional tectonics characterized by the development of mainly NW-SE and NE-SW trending normal faults.

AbstractPresent knowledge on structure and petrology of the various masses of Alpine-Apennine ophiolitic peridotites provides evidence that Triassic-Jurassic rifting and spreading in the Ligurian-Piemontese domain was accomplished through successive stages of lithosphere evolution well recorded in the mantle peridotites.

The early stages of rifting, active during Triassic times, were dominated by overall extension and thinning of the continental lithosphere and exhumation of the sub-continental lithospheric mantle via km-scale extensional shear zones. This represents a tectonic-dominated stage.

Subsequent stages of rifting, starting from Early Jurassic times, were characterized by asthenosphere adiabatic upwelling and decompression melting triggered by lithosphere extension and thinning. These rifting stages were dominated by the interaction of tectonic and magmatic processes. MORB-type melts from the asthenosphere percolated through the overlying lithospheric mantle along the axial zone of the future oceanic basin and large volumes of the extending mantle lithosphere were modified by melt-rock interaction.

Melt percolation induced the thermo-mechanical erosion of the mantle lithosphere resulting in the weakening and softening of the lithosphere. It was a controlling factor in the transition from distributed continental deformation to localised oceanic spreading. MORB magmas intruded the sub-continental mantle along the axial zone of the future oceanic basin forming km-scale gabbroic bodies.

The oceanic stage (i.e. formation of the oceanic lithosphere) was characterized by complete failure of the continental crust during Late Jurassic times, and by the direct exposure of mantle peridotites on the sea-floor. Sub-continental peridotites were exposed at ocean-continent transition (OCT) zones and melt-modified sub-continental peridotites at more internal oceanic (MIO) settings.

MORB magmas reached the sea-floor, extruded above the mantle peridotites to form the oceanic lithosphere (i.e. the association of sub-continental peridotites and Jurassic MORB basalts) of the Ligurian Tethys basin.

AbstractThis paper illustrates the results of structural studies carried out in the western margin of Tuscany along a major crustal structure. Surface deformation of sediments filling different basins aligned on top of this major structure (from north to south: the Fine Basin, the Sassa-Guardistallo basin, the Rio Guardigiano area in the Lustignano basin) allow us to date its tectonic activity to the Messinian-Early Pliocene. In these areas, structures such as reverse and strike-slip faults and mesoscopic folds are widely developed. Structural analysis determined a compressive stress field with the σ1 oriented from E-W to NE-SW active from Messinian to Early Pliocene. At the southern end of this crustal structure, the Gavorrano antiform and the granitic pluton (radiometric age of granite ∼4.4 Ma) coring this fold correlate with a thrust ramp anticline at depth, and thus constrain thrust activity to the Early Pliocene. These data document a Messinian-Early Pliocene compressive activity that contrasts with models invoking continuous extensional tectonics affecting the hinterland since the Late Oligocene-Middle Miocene in the frame of a back-arc-slab retreating process. The results presented therefore raise the question of which geodynamical model could account for such a complex structural evolution of Northern Apennines hinterland.

AbstractThe Scaglia Toscana represents a stratigraphic unit belonging to the Tuscan Domain of the Northern Apennines. Such a stratigraphic unit results lithologically heterogeneous, and is representative of a very long time span (from the Early Cretaceous to the Oligocene) during which very important geological events took place, such as the convergence and collisional events giving rise to the edification of the Northern Apennines orogene. We have studied several key outcrops of the Scaglia Toscana exposed in the Rapolano Terme area (Southern Tuscany, Northern Apennines) in order to contribute to the reconstruction of the depositional setting and palaeogeographical features of a sector of the Tuscan Domain from the Cretaceous to the Early Miocene, and to hypothesise a possible geodynamic evolution.

The Scaglia Toscana exposed in the Rapolano Terme area has been deeply investigated through lithostragraphic and biostratigraphic analyses mainly carried out in three key areas indicated in the fig. 1: 1) the Podere Cetinaia-Podere Monte Petroso section; 2) the Podere Le Rossole section; and 3) the Modanella-Podere Campo d'Aia section. From the top (represented by the overlying Macigno Fm) to the bottom (Maiolica Fm) we have recognized three litostratigraphic units:

2. Silty marls and claystones (Marne siltose ed argilliti marnose rosse di Podere Le Rossole) comparable for the age and stratigraphic position with the Marne del Sugame described in the Chianti Mts. The thickness does not exceed 10 m; Early-Middle Eocene.

The boundary separating the Argilliti di Brolio from the overlying Marne siltose ed argilliti marnose rosse di Podere Le Rossole is representative of a time gap about 7Ma long (from 40 to 47Ma). According to Canuti & Marcucci (1967) we exclude the emersion during this time span, but we support for: i) the reduction of the sedimentation and/or; ii) submarine erosion induced by tectonic instability. Such possible hypotheses can be confirmed by the fact that the gap affects different stratigraphic horizons of the Argilliti di Brolio, and the sedimentation of the Marne siltose ed argilliti marnose rosse di Podere Le Rossole started diachronically. The sedimentary environment of the Marne siltose ed argilliti marnose rosse di Podere Le Rossole is pelagic-hemipelagic, characterised by Foraminifera bearing marly and pelitic sediments. The occurrence of thin bedded calcarenites indicates the formation of a turbidite system, mainly carbonate. Such a turbidite system typifies the overlying succession: the Argilliti e calcareniti di Dudda with interbedded Nummulites bearing calcarenites and calcirudites (Calcareniti di Montegrossi).

The stratigraphic contact between the Argilliti e calcareniti di Dudda and the Marne siltose ed argilliti marnose rosse di Podere Le Rossole lithostratigraphic units is gradual and continuous, and is characterized by the frequency and thickness increase of the turbite beds, as well as by the progressive appearance of the reddish color, moreover characterizing the overlying Marne siltose ed argilliti marnose rosse di Podere Le Rossole. The sedimentological features of the Argilliti e calcareniti di Dudda suggest a radical change of the sedimentary environment. In fact, the hemipelagic sediments were substituted by the turbidite systems. The turbidites are characterized by graded beds containing Eocene planktonic Foraminifera indicating an intrabasinal reworking of penecontemporaneous sediments. Contrarily, the calcarenites of the upper part of the succession are characterized by Cretaceous planktonic Foraminifera being bioclasts indicating an extrabasinal origin. This is indicative for the development of a carbonate turbidite system fed by Cretaceous sediments. The uppermost part of the succession is newly typified by the occurrence of calcarenite beds with intrabasinal Eocene planktonic Foraminifera. Such a lithological assemblage and palaeontological containts became a recurrent feature for the overlying Nummulites bearing calcarenites and calcirudites («Nummulitico», Calcareniti di Montegrossi). Furthermore, these latter are characterized by Eocene benthonic Foraminifera suggesting the development of one or more lobes of a submarine fan channels fed by carbonate platforms. The Nummulite bearing calcarenites are characterized by a trend thinning-fining upward, and gradually pass to the Argilliti e calcareniti di Dudda, indicating the deactivation of the lobe fan system. Such a succession passes to the Macigno siliciclastic sandstone (Macigno Fm).

In sum, we hyphotesise that the embryonal foredeep system of the Northern Apennines could be developed since the Middle-Late Eocene with the activation of a carbonate turbidite system (Argilliti e calcareniti di Dudda plus the Nummulites bearing calcarenites) successively evolved in a siliciclastic turbidite system represented by the Macigno Fm.

The sedimentary gap recorded within the Scaglia Toscana succession could indicate the records of the beginning of the tectonic activity which affected the Tuscan Domain for a long time, related to the development of the Northern Apennines foredeep system.

AbstractThe Ponticello formation is represented by a siliciclastic and calciclastic sedimentary succession, outcropping in the campanian sector of the Southern Apennines, and structured in four main sequences (lithozones). A transition interval is localized in the upper portion of the sedimentary record.

A lithozone CTS (Calcarenitic Turbiditic Sequence), with dominant marly deposits is constituted by yellow, medium, sometimes coarse grained stratified calcarenites, occasionally weakly cemented. The bed thickness varies from a few centimeters to several decimeters, with many showing the Bouma Sequence. In the Arenara and Melito Vecchia locations frequent intervals of marls, marly limestones, and rarely «pseudo-saccharoidal» limestones crop out. An intense bioturbation is present. The deposits of this interval are approximately 25 meters thick and originated by turbiditic processes.

A lithozone SCS (Sandy-microConglomeratic Sequence), with dominant arenaceous-conglomeratic deposits, comprises alternations of medium-coarse grained yellow-brownish sands with quartzo-feldspathic composition, and paraconglomerates. In places this interval includes some layers of granular conglomerates, with sub-rounded polygenic clasts, immersed in a sandy matrix. The sands are organized in layers some decimetres thick. The paraconglomerates are usually organized in fining-up sequences. The thickness of this lithozone is approximately 40 meters, the significant exposures being in the Vallone dei Morti. The deposits of this lithozone can be interpreted as formed by submarine mass flows and gravity flows.

A lithozone MCS (Marly-Calcareous Sequence), with marly-limestone dominant, consists of alternations of marls, calcareous marls and white marly limestones, ordered in layers which generally have a maximum thickness of 10-15 centimeters, and usually contain an abundant planktonic microfauna. The thickness of this lithozone seems to exceed 50 meters in the Incoronata and Felette locations. The sediments of this interval can be considered as the result of depositional processes that occur along a submarine slope.

Above the lithozone MCS lies a transitional stratigraphic interval, well exposed along the Vallone Ponticello, and characterized by two dominant components: a calciclastic portion (TCC), in the lower part, and a siliciclastic fraction (TSC), in the upper part. The lower part, about 20 meters thick, crops out in the C. Sterpara and Pretalonga locations, shows alternations of partially recrystallized calcarenites and calcareous brecciola. This last lithotype is characterized by lithoclastic (calcilutites, oolithic limestones, etc.) and bioclastic (Lithothamnium and briozoarians, pectinids, etc.) elements, granule to fine pebble size and frequently angular-shaped, inter-bedded with marly limestones and marls. In the C. Sterpara location, the upper transition interval (TSC), approximately 25 meters thick, also outcrops. It is constituted by sandstones, siltstones and marls, with very frequent intercalations of alternating of light grey muddy marls and brownish muddy silts, outcropping in Incoronata location. Here a polygenetic orthoconglomerate horizon more than one meter thick is present, containing an important crystalline fraction (mostly granitoids). The clast dimensions are commonly larger than ten centimetres, the sorting is moderate, and a short supply of the arenaceous-microconglomeratic matrix is manifest. The transition interval can be interpreted as connected to processes of detritic sedimentation in proximal sectors of the marine basin, near the coastline.

A lithozone ATS (Arenaceous Turbiditic Sequence) with arenaceous-pelitic compositions dominant, consists of brownish-yellow, [or yellowish-brown!] medium to fine grained, quartzo-feldspathic sandstones and laminated muds. Usually the complete Bouma Sequence is recognizable. The best exposure is in the C. Sterpara location, where this interval reaches a thickness of approximately 30 meters. This interval can be interpreted as the result of submarine turbiditic flows.

The calciclastic fraction originates from the erosion of several units of the Southern Apennine chain. The supply areas of the calcareous clasts are identifiable with the Mesozoic carbonate platform unit, mainly from outer positions. In the lower part of the transition interval (TCC) the presence of fragments of limestones with Lithothamnium and briozoarians indicates the probable erosion of Miocene successions (Formazione di Cusano and Formazione di Longano, SELLI, 1957) overlying some external platforms.

The source areas of the siliciclastic sediments, instead, derive from the erosion of deposits previously involved in the orogenic transport. The rich presence of crystalline clasts in the upper portion of the transition interval (TSC), is due to probable reworking of inner units of the sudappennine chain (cfr. Gruppo del Cilento, AMORE et alii, 1988).

The supra-Miocene deposits of the Ponticello Formation are the expression of an intermontane basin, carried on the Southern Apennine nappes, in thrust-top position.